Explanation: MAXMIGRATIONTASKS(nn) is an optional parameter specifying the maximum number of automatic volume space management (primary space management, interval migration and on-demand migration) tasks that can run concurrently. It applies to the processing of primary volumes and SMS-managed volumes. You can specify the maximum number of concurrent tasks (nn) from 1 to 15.
MAXMIGRATIONTASKS applies only to automatic functions. You can run only one command migration task at a time. Individual commands for data set or volume migrations do not run concurrently.
Tape units must be available to support the maximum number of migration tasks. In a direct-to-tape environment, the number of tape units available must be at least equal to nn. The number of SDSP data sets available should be greater than nn. In addition, in a duplex tape environment, the number of tape units must be at least 2 times nn.
In the environment where data sets can be routed to either DASD or tape, a tape unit is required for each migration task that encounters a data set to be migrated directly to tape. Make sure that you have nn tape units available. Once DFSMShsm has selected a tape unit, it will not be released until the automatic volume space management function has completed. In a duplex tape environment, DFSMShsm selects two tape units for each migration task and these tape units will not be released until the automatic volume space management function is complete. This does not apply to DASD volumes.
SMS relationship: Parameter has the same meaning when applied to SMS-managed or non-SMS-managed DASD volumes or data sets.
SETSYS default: None.
DFSMShsm default: If you do not specify this parameter on any SETSYS command, the default value for the maximum number of concurrent migration tasks (nn) is 2.